[llvm] [VPlan] Add initial VPScalarEvolution, use to get trip count SCEV (NFC) (PR #94464)

[via llvm-commits]

================
@@ -67,6 +69,15 @@ class VPTypeAnalysis {
 // Collect a VPlan's ephemeral recipes (those used only by an assume).
 void collectEphemeralRecipesForVPlan(VPlan &Plan,
                                      DenseSet<VPRecipeBase *> &EphRecipes);
+
+namespace vputils {
+
+/// Return the SCEV expression for \p V. Returns SCEVCouldNotCompute if no
+/// SCEV expression could be constructed.
+const SCEV *getSCEVExprForVPValue(VPValue *V, ScalarEvolution &SE);
----------------
ayalz wrote:

Does this more naturally belong to VPlan.h and VPlan.cpp, alongside other vputils functions, in particular the complementary vputils::getOrCreateVPValueForSCEVExpr()?

https://github.com/llvm/llvm-project/pull/94464